GaN Schottky Diode EMI Shielding via Cathode Isolation
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Solution Overview
Problem
Schottky diodes, particularly those with GaN and AlGaN layers, face issues with electromagnetic interference (EMI) and current collapse, which degrade their performance, especially when the cathode is connected to the backside of the substrate.
Innovation Solution
A semiconductor device design where the cathode and a first electrically conductive portion of the carrier are electrically isolated from the backside of the substrate, with the first conductive portion configured to provide shielding against EMI, and the anode is connected to the backside or left floating, reducing current collapse effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cathode is connected to the backside of the substrate, then electrical communication between cathode and substrate is achieved, but electromagnetic interference and current collapse occur
Solution Approach 1:
The substrate is divided into a front surface and a backside, with the cathode connected to the front surface while the backside is electrically isolated. This segmentation allows the cathode to maintain electrical communication through the front surface connection while preventing harmful electromagnetic interference that would occur with backside connection.
Solution Approach 2:
The harmful electrical connection between the backside of the substrate and the cathode is extracted/removed. By preventing the backside from being electrically connected to the cathode, the source of electromagnetic interference and current collapse is eliminated while the necessary electrical communication is maintained through the front surface connection.
2Ease of operation
If the anode is switched between large negative voltage and low positive voltage, then rectification function is achieved, but electromagnetic radiation causes electromagnetic interference
Solution Approach 1:
The electromagnetic radiation generated during anode switching is converted into a beneficial shielding effect. By providing an electrically conductive shield connected to the cathode, the harmful electromagnetic radiation is redirected and contained, transforming it into a protective mechanism that reduces overall electromagnetic interference.
Solution Approach 2:
An electrically conductive shield is introduced as an intermediary between the anode and the external environment. This shield mediates the electromagnetic radiation by providing a controlled path for the electromagnetic energy, reducing the harmful interference while allowing the rectification function to operate normally.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces electromagnetic interference and minimizes current collapse, enhancing the performance of Schottky diodes by isolating the cathode from the backside substrate and shielding the anode, leading to improved forward current characteristics.
Implementation Method 1
The first electrically conductive portion of the carrier is configured to provide shielding against electromagnetic interference associated with switching of the anode during operation of the device
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
A semiconductor device and a method of making the same. The semiconductor device includes a semiconductor substrate (70) mounted on a carrier. The semiconductor substrate includes a Schottky diode. The Schottky diode has an anode (58) and a cathode (56). The semiconductor device also includes one or more bond wires (66) connecting the cathode (56) to a first electrically conductive portion (52A) of the carrier. The semiconductor device further includes one or more bond wires (68) connecting the anode (58) to a second electrically conductive portion (52B) of the carrier. The first electrically conductive portion (52A) of the carrier is electrically isolated from the second electrically conductive portion (52B) of the carrier. The first electrically conductive portion (52A) of the carrier is configured to provide shielding against electromagnetic interference associated with switching of the anode (58) during operation of the device. Both the cathode (56) and the first electrically conductive portion (52A) of the carrier are electrically isolated from a backside of the semiconductor substrate (70).